Preconditioning for EDA cell library

Abstract

A characterized cell library for EDA tools includes one or more mathematical models for each cell, and one or more preconditioning functions (and/or inverse preconditioning functions) for each mathematical model. Each mathematical model represents a performance parameter (e.g., delay, power consumption, noise) or a preconditioned performance parameter of the cell. The preconditioning functions convert an operating parameter (e.g., input slew, output capacitance) associated with the performance parameter into a preconditioned input variable for the mathematical models. In doing so, the preconditioning functions allow for more accurate modeling of complex data relationships without increasing the complexity (e.g., order and number of coefficients) of the mathematical models. Also, because the cell library can be substantially similar to conventional polynomial-based cell libraries except for the inclusion of preconditioning functions, preconditioning does not significantly increase storage requirements and conventional EDA tools can be readily adapted to use the preconditioned cell library.

The invention claimed is: 
     
       1. A cell library comprising:
 a first cell identifier, the first cell identifier corresponding to a first cell; 
 a first preconditioning function for generating a first input variable from a first operational parameter, the first preconditioning function being associated with the first cell identifier; and 
 a first mathematical model for generating an output value for a first performance parameter, the first mathematical model being a function of the first input variable, and the first mathematical model being associated with the first cell identifier. 
 
     
     
       2. The cell library of  claim 1 , wherein the cell library further comprises a second preconditioning function for generating a second input variable from a second operational parameter,
 wherein the second preconditioning function is associated with the first cell identifier, and 
 wherein the first mathematical model is further a function of the second input variable. 
 
     
     
       3. The cell library of  claim 1 , wherein the first mathematical model is further a function of a second operational parameter. 
     
     
       4. The cell library of  claim 1 , wherein the first preconditioning function is further a function of a second operational parameter. 
     
     
       5. The cell library of  claim 1 , wherein the first mathematical model comprises a scalable polynomial model. 
     
     
       6. The cell library of  claim 1 , wherein the first performance parameter is one of delay, transition time, power consumption, and noise. 
     
     
       7. The cell library of  claim 1 , wherein the first performance parameter comprises delay, and wherein the first operational parameter comprises one of input slew, output capacitance, temperature, and voltage. 
     
     
       8. A cell library comprising:
 a first cell identifier, the first cell identifier corresponding to a first cell; 
 a first inverse preconditioning function for generating a first performance parameter from a first preconditioned performance parameter, the first inverse preconditioning function being associated with the first cell identifier; and 
 a first mathematical model for generating an output value for the first preconditioned performance parameter, the first mathematical model being associated with the first cell identifier. 
 
     
     
       9. The cell library of  claim 8 , further comprising a first preconditioning function for generating a first input variable from a first operational parameter, the first preconditioning function being associated with the first cell identifier, wherein the first mathematical model is a function of the first input variable. 
     
     
       10. The cell library of  claim 8 , further comprising a second preconditioning function for generating a second input variable from a second operational parameter, the second preconditioning function being associated with the first cell identifier, wherein the first mathematical model is a function of the first input variable and the second input variable. 
     
     
       11. The cell library of  claim 8 , wherein the first mathematical model comprises a scalable polynomial model.